I'm looking at buying an Alpine CDA-9833 from a friend, and I was wondering what it's worth. It's from 2004, and has a couple issues. The MP3 reading is fairly slow, and the volume knob is glitchy. it sometimes wont go up or down, sometimes it will go down when you turn it up, and sometimes it does the opposite of that. The face is scratched a bit, about the average for being the age.